High melting point wax



E. R. WILES HIGH MELTING POINT wAx IVDMn 22, 1942.

Filed June 3, 19259 WQTQQKM. .NEMA QQ@ INVENTOR. Erve!! JY. Iii/g; BY

Alaya/, 4114/17* ATTORNEYS ularly,

Patented' Dec. 22, 1942 2,306,201 HIGH MELTING roTN'r Wax Everett R.Wiles, Barnsdall, Okla., asslgnor to Bareco Oil Company, Tulsa, Okla., acorporation of Delaware Application June 3, 1939,'Serial No. 277,221

4 Claims.

The present invention relates to high melting point waxes which may bederived from petroleum, by means of the process disclosed in my UnitedStates Patent No. 2,123,982, granted July 19, 1938. The presentapplication is a continuation-in-part of my application Serial No.114,753, iiled December 8, 1936, which is, in turn, a division ofapplication Serial No. 66,445, now Patent No. 2,123,982. v

Prior types of high melting point waxes have, in common, thedisadvantage of being comparatively non-adhesive, brittle and hard whentheir temperature is reduced to about F. While these characteristics maynot use of such waxes for many purposes when high melting point,vonlinis required, there are many other uses to which they cannot beput. For example, such hard and brittle high melting point waxes cannotbe used satisfactorily for lining metallic containers for beverages orfoodstuffs which are chilled to low temperature, for the reason that thewaxes will'crack or break away from the walls of the containers and thusexpose the metal and cause undesirable avors to develop in the contents.

If attempts are made to reduce the brittleness of the waxes by addingoil or other diluent, the melting points of the waxes are lowered andthey become tacky or sticky. Furthermore, the oil prevents their useunder conditions where the waxes may be brought into contact withmaterials which may be stained or given off" avors.

An object of the present invention is to provide high melting pointwaxes which are oil-free and are ductile and adhesive atlower`temperatures, without being sticky or tacky at normal temperatureor even above.

Another object of the invention is to provide oil-free waxes havingmelting points of 155 F. and above, which are ductile and will adhere tometal over a wide range of temperatures.

Waxes embodying the present invention are derived from petrolatum andare characterized by having melting points of 155?. or above, and eventhough oil-free are so ductile that they may be bent sharply attemperatures as low as 32 F. without cracking and shattering. Moreparticthese waxes are characterized by a needlelike microcrystallinestructurewhich appears to impart excellent ductility to them and theyare so adhesive that when spread as a nlm on a sheet of polished metal,the waxes will adhere to the metal and will not separate or crack offthe metal when the latter is chilled to 32 F. and bent sharply. Theadhesiveness and ductility adversely affect the' the wax, .when cold,

of the waxes are remarkable in view of the fact that the waxes are notsticky or tacky at temperatures well above room temperature, and aresubstantially entirely free of oil.

As described in my Patent No. 2,123,982, granted July 19, 1938, and inaccordance with the process set forth hereinafter, waxes embodying theinvention maybe produced from petrolatum.

A typical iiow diagram of the process is illustrated in theaccompanyingdrawing.

The petrolatum from which thewax is produced may be obtained frompetroleum in any of the conventional ways. This petrolatum is collectedin a storage tank drawn and charged to a still. In the still it isreduced by distillation with steam' or a high vacuum or both to aresidue consisting of about 20% to 50% of the starting stock and havinga. flash point of at least 500 F. Substantially: al1 the waxes whichtend to impart brittleness to and low boiling hydrocarbon oils areremoved by this distillation. Cuiilcient steam or suniclently highvacuum should be used so that any decomposition of the stock isminimlzed. When a' vacuum is used for this purpose, an absolute pressureof 5-30 mm. is preferred.

The residue resulting from the steam or vacuum distillation is run to aresiduum storage tank. Onek part of the residue is withdrawn and isheated to a temperature of approximately 180 F., plus or minus- 10, andmixed with and dissolved in approximately four to six parts of ethylenedichloride, or a mixture of solvents, such as benzol and acetone ornaphtha and butanol in a mixing tank.

The solvent used, preferably ethylene dichloride, is characterized bythe ability to dis'- solve waxes at approximately 180 F. but at a lowertemperature, that is F., causes precipitation oi' the waxes inillterable form.

The mixture of solvent, wax and some occluded oil, is agitated bysuitable means while the temperature of the mixture is reduced to apredetermined point. Themeltlng point of the final wax product dependsupon the temperature to which the mixture is reduced. If, for example,it is desired to produce a wax with a melting point of F., the mixtureis cooled to 80 F. and maintained at this temperature over a period upto four hours, while being constantly agitated. The agitation causesformation of lterable clumps or aggregates of microcrystals of the waxwhich are removed in a manner hereinafter described.

The treatment in the agitating tank depends from which it 4is withtosome degree upon the condition of the charging stock. If the originalstock is dark in color, approaching black, indicating the presence of aconsiderable proportion of asphaltic bodies. it may be advisable tomaintain the conditions in the agitating tank for an extended period oftime, for example, four hours or more. If the original stock is light incolor, it may be treated in the tank for a much shorter time, forexample, an hour, or even less. The presence of asphaltic bodies appears,to retard crystal formation, thereby necessitating an increase in thelength of time of agitation.

When the precipitated wax has attained a i'llterable form, it is passedto a filter press, for removal of the wax.

'I'he preferred form of filter press is one having canvas or papercovered rotatable leaves enclosed in a vapor-tight case, capable ofwithstanding a pressure of 50 pounds per square inch, and havingadditional inlet nozzles adjacent the leaves of the press for a purpose'later to be described.

A sumcient quantity of the mixture of crystallized wax, solvent andoccluded oil is pumped into the press to deposit a layer of the wax ofappreciable thickness on the leaves of the press,

and the excess solvent, oil and undeposited wax is blown from the pressby gas under pressure. The gas pressure is maintained in the. presswhile clean ethylene dichloridelis forced through the cake to wash andremove oil therefrom. 'Ihe washing is continued until the ltrate comingfrom the lter press is free from-oil, at which time the remainder of thesolvent is blown out by the gas under pressure. It is important thatdurlngthe whole filtering and washing operation, the pressure withinvthe filter should not be allowed to drop because otherwise the cakes ofwax would fall from the filter leaves, rendering washing of the waxcakes impossible. A

At the conclusion of the washing and draining steps, clean ethylenedichloride is forced through the nozzles arranged adjacent the filterleaves to strip the wax cakes therefrom -and mix them with the solvent.The mixture is then transferred to a still where the temperature israised to a point suillciently high to distill 'off the solvent,refiuxing being used to assure a clean separation of the solvent and thewax. The residue-is cooled,v and if colored may be further treated inany conventional manner such as with fullers earth, to produce asubstantially colorless wax.

' What occurs in the preceding process is believed to be as follows: g

The distillation of the petrolatum stock .to produce a bottoms having aflash point of above 500 F., eliminates the waxes causing coldbrittleness and most of the lower boiling point oils in the stock, thusproducing a bottoms residue which contains only waxes having highmelting aration is produced, eliminating al1 of the ethylene dichloride,and permitting formation of very fine needle-like crystals in the finalproduct.

It will thus be understood that the described process avoids thenecessity of repeated crystallizations of the wax, and thus reduces notonly the time required to obtain the final product, but also results inthe desired feature of treating a relatively smaller amount of theoriginal petrolatum stock with the solvents, thus rendering the processmore economical. It will also be understood that the treatment of thestock will require less time, and thereby permits a greater amount ofmaterial to be treated in a given time with a consequently greater yieldof product than has heretofore been possible.

The remelting and distillation steps change the crystalline structure ofthe wax from coarse crystalline to microcrystalline by the removal ofsolvent. The resulting waxes have greatly improved physicalcharacteristics. The reduced size of the crystals causes the wax to havegreater ductillty overa wide temperature range probably because ofinter-crystalline slippage, and for some reason.

not clearly understood, the wax is very adhesive over an equally widerange of temperatures.

By way of a specific embodiment of applicants process, petrolatumobtained from the Barnsdall Refining Company was distilled to 50%bottoms, and a flash point of approximately550 F. To one volume ofthe.50% bottoms were added four to six volumes of ethylene dichlride;solution of the residue in the solvent being eected at 175 F. Thesolution was then cooled to "A F. and agitated to produce a lterableform of wax, then filtered and washed in a. filter press having `duckcoverings on vthe leaves.V After vwashing with ethylene dichloride, the,cakes of wax were again dissolvedv in ethylene dichloride and thesolvent then distilled leaving a wax residue.

The wax produced had a melting point of 161.5 F. and a refractive indexat 176 F. of 1.4524 and when examined under a microscope, with polarizedlight, disclosed a fine crystalline structure, containing needle-likecrystals.

A sample of this wax was melted and spread on a tin sheet, and chilledto 32 F., and upon bending of the sheet sharply, no fracture wasproduced in the wax coating, thereby showing that the ductility of thewaxeven at low temperatures was very satisfactory. Not only that, butthe wax coating vdid not chip or ake from the sheet, thereby disclosinga property of -improved adhesiveness.

. fI'hree other waxes produced from Barnsdalls petrolatmn in a similarmanner gave the following values:

M. 1. D 116 rl F. i B 15114 1.4520 'o 180.1 1.4510 160.1 1.4545

a1sso1v1ng the wax and distuimg, a clean sepf5 Other typical waxesembodying the invention which differed in their color due to thepresence of varying amounts of coloring matter were tested to determinetheir refractive indices and also for du'rometer hardness in order todetermine their hardness at a numberof difl'erenttemperatures.

The Shore durometer is an instrument which is very widely used fordetermining the hardness of rubber. The type of instrument used in thedurometer test is the type used for ordinary soft rubber. It contains ablunt pin which is sup-` Barnsdall waxes D. H. at 86 F.

D. H. at 113 F.

D. H.l

nD 176 F.

The results of these tests show that the waxes embodying the presentinvention are comparatively soft even at low temperatures despite theirhigh melting points.

Moreover, in order to determine the hardness of the waxes on a differentbasis, they were tested at various temperatures with a penetrometer, aninstrument commonly used for measuring the hardness of plasticmaterials. The results of these tests are as follows:

Penetrations (100 grams-5 seconds) 32 F. 50 F. 17 F. 100 F. 115 F.

White 9 14 16 35 57 Yellow 8 14 17 34 64 Brown 9 14 18 35 61 My waxproduct disclosed herein is particularly suitable for lining metalcontainers for beverages and other foodstuffs. The adhesiveness of thewax permits a ilrm and permanent bond with the metal surface. Previouslyit has been diiricult if not impossible to line beverage containerssatisfactorily because of the tendency. of the lining material to becomebrittle and break away from the metal surface. This allows the beverageto come in contact with the metal surface, with resulting ilavorcontamination.- The high ductility of this wax, even at low'.temperatures, avoids any possibility of the wax becoming loose from thesurface of a beverage container when dented, bent or subjected to asudden blow.

It should beparticularly noted that the ductility even at lowtemperatures is accomplished without any addition of liquid or oilymaterials,

and thus there is no possibility of the beverageg absorbing undesirablecomponents from the wax liner. My wax is tasteless and odorless and thusideally suited for use with food products. It should also be noted thatthe wax maintains its desirable characteristics even at relatively hightemperatures and has a melting point in excess ot 155 F. Thus, there isno melting of a wax liner made from my product when such a container issubjected to pasteurizing conditions.

I claim:

1. A high melting point petroleum wax of high ductility yetsubstantially oil-free and non-tacky. said wax having a melting point ofat least 155, and a durometer hardness of not more than 85 at 32 F..said wax being so ductile that a thin lm thereof may be .bent sharply at32 F. without cracking and shattering.

2. A high melting point petroleum wax of high ductility yetsubstantially oil-free and non-taclw, said wax having a melting point ofat least 155, and a durometer` hardness of not more than 85 at 32 F.,said waxv being so adhesive and ductile that when the wax is applied toa metallic sheet and the latter bent sharply at temperatures as low as32 F., the wax will not crack or separate from said sheet.

3. A high melting point petroleum wax of high ductility yetsubstantially oil-free and non-tacky, said wax having a melting pointoi' about-160 F., a durometerhardnessof not vmore than 85 at 32 F. and arefractive index between about 1.4475 and 1.4545 at 176 F., said waxbeing so ductile that a thin fllm thereof may be bent sharply attemperatures as low as 32 F. without cracking.

4. A high melting point petroleum wax of high ductility yetsubstantially oil-free and non-tacky,

EVERETTRWIIES.

CERTlFIc'ATE oF CORRECT-10N'. l Patent No. 2,306,201. -December22,.19l|.2,

EVERETT R. wILEs.

It is hereby [certified that-error 'appears-1n the. printedspecification of the above numbered patent requiring 'correction asfollows: 'Page 5 -,'Tab1e -1 I, 6th bolumn thereof,- for l end-that thesaid Letters Ptetshould be read. withrthiscorrection'there- 1n that thesame may conform to the 'recorder thecase in the Patent Officm signedand sealed .this 9th day of February, A; n. 19M.

Henry Van Arsdae, Seal) Acting Commissioner of Patents.

